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Health Mythbusters ‑ Green Tea: All it's cracked up to be?

Posted by Dawn Morrison on March 1, 2018 in News, Research, Innovation

Mythbusters Tannis Jurgens (left) and Anne Marie Whelan. (Trudi Smith photo)

In the age of ‘fake news,’ relying on research and fact-based data to make decisions about our health is more important than ever. Health Mythbusters is a regular column in which Dal Health researchers challenge widely held beliefs about health issues. This month, Dr. Tannis Jurgens and Dr. Anne Marie Whelan look at green tea products for weight loss — do they really work?

Tannis Jurgens is a professor in the College of Pharmacy. Among other things, her research is focused on natural health products — evaluating the efficacy and safety of these products when it comes to women’s health. She and her team use systematic review methodology to guide the critical appraisal of clinical trials.

Anne Marie Whelan is a professor and associate director of program evaluation for the College of Pharmacy. Her primary program of research is women’s health with additional work in the areas of pharmacy education, program evaluation, and pharmacy practice.

Five questions for Dr. Jurgens and Dr. Whelan:

1) Dal Health: What are some of the more outlandish claims you’ve heard about health-related products?

TJ: The idea that we need to detoxify our bodies using natural health products. There are a lot of products marketed to rid your body of toxins, when your body does a pretty good job of doing that on its own through your lungs, liver, skin, and respiratory system.

AMW: I read about a contraceptive method in the form of an app that was essentially a very old and unreliable method. It was repackaged as something new by putting some tech around it and presenting it as something ‘natural’ and non-drug-based. Unfortunately, there were pregnancies that occurred in some of the women that were using it for contraception.

2) Dal Health: Why do you think there is so much misinformation out there about natural health products in general?

TJ:  I think people today want to take ownership over their own health. We tend to want to find our own solutions and take charge of our own health challenges. This could mean anything from searching for health information online or taking advice from a neighbour. There’s also accessibility to consider — there is a huge amount of information available at our fingertips. A quick Google search lets people find information about natural health products, however not all of the information may be dependable. Also, many of the companies that make these products advertise widely to the public. With all the information available it is sometimes hard for consumers to sort through it all.

3) Dal Health: There are claims that green tea products can help people lose weight. Is this claim true?

AMW: Green tea products are marketed to help with weight loss, so we wanted to see if there was really strong evidence behind the claims on the label. We looked very closely at a lot of studies and found some evidence of weight loss, however most findings were not clinically relevant. And that was with green tea supplements— not a cup of green tea.

TJ: Combining the results of studies showed a weight loss ranging from 0.02 to 3.5 kgs over 3 months. A person might be happy with that level of weight loss over some months, but it’s thought that you need to lose five to 10% of total body weight to see significant health benefits.

4) Dal Health: Are there any health risks associated with taking green tea products?

TJ: Many people see the word “natural” on the label and think they can take it and there will be no harm done. That’s true in a lot of cases, but not for everyone. Unfortunately, some of the earlier trials of green tea products didn’t record adverse effects. That doesn’t mean they didn’t happen. More recently, adverse effects are being reported.  For example, for a small percentage of people, green tea products in large doses can cause liver damage. It’s rare, but it happens. So, ‘natural’ doesn’t necessarily always mean ‘safe` and green tea products should be used with caution.

5) Dal Health: So, what is the bottom line when it comes to whether or not to take green tea products for weight loss?

AMW: Taking green tea products might give you some momentum in losing a small amount of weight. The bottom line is that if you’re going to take green tea products for weight loss, just know that it might work and it might not.